fix: parse pcks8 private key issue

[shipengqi]

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Please add a summary of your change

fix parse pcks8 private key issue

Does your change fix a particular issue?

Fixes #(issue)

#33

Check list:

• Mark if documentation changes are required.
• Mark if tests were added or updated to cover the changes.

[codecov-commenter]

Codecov Report

Merging #34 (7a9f6cb) into main (dc19c24) will increase coverage by 0.14%.
The diff coverage is 58.33%.

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@@            Coverage Diff             @@
##             main      #34      +/-   ##
==========================================
+ Coverage   71.50%   71.65%   +0.14%     
==========================================
  Files          22       22              
  Lines         958      963       +5     
==========================================
+ Hits          685      690       +5     
  Misses        198      198              
  Partials       75       75              

Flag	Coverage Δ
unittests	71.65% <58.33%> (+0.14%)	⬆️

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Files Changed	Coverage Δ
crtutil/key.go	48.00% <0.00%> (ø)
fsutil/tar.go	51.61% <ø> (ø)
sysutil/sys_unix.go	75.00% <ø> (ø)
strutil/str.go	100.00% <100.00%> (ø)
sysutil/sys.go	78.00% <100.00%> (+2.44%)	⬆️

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